Elevator switch



March 16, 1948. FQPETRULLO ELEVATOR SWITCH Filed Feb. 17,- 1945 W' Nimh. 'IIN INVENTOR. 10e zzzZlo A T TOR N Y fvelz'ce BY JIU menno Mer. 16,-1948 2,438,094

UNITED STATES PATENT OFFICE ELEvA'ron swrron Felice Petrullo,` Jersey City, N. J., assignor to Industrial Patents Corporation, Chicago, Ill., a corporation of Delaware Application February 17, 1945, Serial No. 578,373 1 Claim. (Cl. 171-97) This invention relates to a switch and more particularly to a tamper proof switch especially suitable for use in elevator controls.

In modern elevator controls, interlocking played.

Referring to the drawings, the switch of Figures 1 and 2 may include a casing I0 provided with a. cover Il which may be secured to the casing III in any desired manner so as to be capa- 2 ble of being sealed or locked to the casing IIl,

for example, by a pin I2 and a seal I3. The cas' ing IIl may be provided with an elongated tubular member I4 projecting from one side thereof switches actuated by the doors of the elevator 5 to form a guide opening I 6 for a switch actuaare usually employed to disable the elevator contor Il. The tubular member I4 may be welded trol circuit to prevent movement of the elevator or otherwise suitably secured to the casing I0 when any door is open. The switches referred to prevent removal thereof from the exterior of to are provided forsafety purposes to prevent inthe casing. jury to elevator operators, passengers, etc. Parl0 The Casing I0 may Contain a pair of spring ticularly in the case of freight elevators, the contact members I9 and I9 suitably secured, for operators thereof, in disregard of safety reguexample, by rivets 20 to insulating members 2I lations, frequently tamper with the safety and 22 secured to the top and bottom walls oi switches in order to permit operation of the eiethe casing, for example, by rivets 23. The convator with the doors open. The present inventact members have their contact portions in tion provides a switch which is extremely diiiicuit alignment with the actuator aperture I6 for Conto actuate with the door open without destructact with the actuator Il when said actuator is tion of the'lock or seal of the switch casing or inserted through the aperture I6. The casing the disabling of the elevator control circuit. Inmay also contain a fuse 24 Supported in Suitasertion of a member of insulating material into ble fuse clips 26 and 2l in turn Supported 1113011 a the switch actuator aperture will not render the block of insulating material 28 secured to the elevator control switch operative and insertion of base of the casing. Conductors 29 and 3|, for an electrically conducting member will disable example, the conductors of a standard BX cable the elevator control circuit until repaired by an 32 may enter the casing through a cable connecauthorized person. tor 33. The spring contacts I3 and I9 may be It is therefore an object of the invention to connected in a series circuit with the fuse 24 provide a substantially tamper proof safety and the conductors 29 and 3|, a short conductor switch for elevator doors and similar structures. 29a being employed to connect the fuse clip 2l Another object of the invention is to provide with the spring contact I9. an improved elevator safety switch which is dif- The spring contacts I8 and I9 normally occucult to actuate to enable the elevator to be py the positions shown in Figure 1 so that the moved except by the actuator operated by closing circuit through the switch box is open, the cirofthe elevator doors. cuit being closed between the contacts I8 andv A further object of the invention is to provide a I9 upon insertion of the actuator I'I. This acsai'ety switch for elevator doors which either is 35 tuator may include a body member 34 of either not actuated or which completely disables the conducting or non-conducting material although elevator control circuit when an attempt is made the body member is preferably made of a section to introduce an incorrect actuator into the acof small iron pipe. The inner end portion 36 of tuator aperture of the switch. the actuator I I is, however, constructed of in- Other objects and advantages of the invention 40 sulating material provided with a metallic band will become apparent from the following descrip- 39 intermediate its ends. The insulating mate-- tion of preferred embodiments of the invention rial 36 may be secured to the body portion 34 of shown in the attached drawings of which the actuator in any desired manner (not shown). Figure 1 is a vertical section through a switch The actuator Il may also be provided with a stop of the present invention showing an actuator member 4I so that movement of the actuator to therefor; the right in Figure 1, until the stop member 4I Figure 2 is a vertical section taken on the line contacts the guide member I4, positions the 2-2 of Figure 1; conducting band 39 of the actuator between the Figure 3 is a fragmentary section showing a spring contacts I8 and I9 to complete the cirmodiilcatiou of a portion of the switch of Fig 5o cuit through the switch. It will be apparent that ure 1; insertion of a member of insulating material Figure 4 illustrates o ne type of circuit in which such as a rod of wood into the switch can not the present switch can be employed; and complete a circuit through the switch and that Figure 5 illustrates a modified circuit in which insertion of a member of electrically conducting the switch of the present invention can be emmaterial such as a rod of metal into the switch will produce an electrical connection between the contacts I8 and I9 and the switch casing.

For purposes of illustration, a circuit is shown in Figure 4 which can. be employed with the switch of Figures 1 and 2. Two switches each including spring contacts I8 and I9 are shown in Figure 4, each pair of contacts being associated with a fuse 24. The contacts of the two switches and the fuses 24 may be connected in series with a source of voltage 42. When a circuit is completed through both sets of` contacts I8 and I9, the elevator control circuit including the conductors 44 is closed to enable movement of the elevator. It will be apparent that as many switches as there are doors on the particular elevator may be employed in the series circuit. It will be further apparent that an actuator such as the actuator I1 shown in Figure 1 must be employed to complete the circuit between the contacts I8 and I9. An insulating member will not close this circuit. Furthermore, the guide member I4ffor the actuator is shown as being connected to ground and one terminal of the source 42 is also shown as being connected to ground at46. Insertion of 'a conducting member through the guide I4 must contact both contacts I8` and I9`to complete the circuit and upon engaging contact I9 and the guide member I4', a

vshort circuit through a fuse 24 will be produced causing blowing thereof so as'tov completely disable the control circuit preventing operation `oi lthe elevator.' `Movement Aof the elevator can not L then be-accomplished until the blown fuse 24 has been replacedr'and; all doors closed.

In cases where it isj undesirable to ground one lside ofthesourcef42 or to have the casing I0 Y cf thev switch electrically Iconnected to the source,

the actuator lguide structure of Figure 3 may be employed. sleeve 41 is shown as being insulated from an outer sleeve 48 by means of an `insulating, sleeve 49 and an insulating washer 5I. The conducting sleeve 41v may have a portion 52` projecting internally oi the casing I for connection to one side of the source of electric voltage. The structure of Figure 3 can be advantageously employed in the circuit of Figure 5 in which the contacts I8 and I9 of a plurality of switches are each in a series circuit including a fuse 24 and a relay 53, these series circuits being connected in parallel across a source 42 of voltage. The conducting sleeves 4l are 'connected to one side of the source 42 so that insertion of a conducting member through the sleeve 41 will short circuit contact I9 through its associated fuse 24, thus disabling the circuit so that the associated relay 53 can not be closed. Since closure of both relays 53 is necessary to close. the control circuit, including the conductors 54, the elevator can not be operated until the blown fuse 24 is replaced.

It will be apparent that the grounded sleeve I4 of the switch of Figure 1 can be employed in the circuit of Figure 5y by connecting the casing I9 in the same manner as the sleeve 41 of Figure 5 is shown connected and that the insulating guide sleeve of Figure 3 can be employed in the circuit of Figure 4 by connecting the same to ground. The specic structures shown in Figures 1 to 3 are by way of example as various other arrangements of contacts and actuator guides can be employed. By employing an elongated conducting guide member for the actuator and arranging the contacts to close the circuit only when a conductingvportion of the actuator, insulated from the main body of the actuator, is between the contacts, it is extremely difficult to actuate the switch with any instrumentality other than a In this figure, a conducting inner i properly designed actuator, not ordinarily available to elevator operators and other employees using the elevators. It is, therefore, extremely diicult for such employees to condition the control circuit for elevator movement when the doors of the elevator are open. Also the circuits of Figures 4 and 5 are merely illustrative as the switch is capable of being employed in any one of a large number of different circuits including control circuits for structures other than elevators. That is to say, the switch has utility wherever it is desired to prevent closing of a circuitexcept by a properly designed actuator.

While I have disclosed the preferred embodiments of my invention, it is understood that the details thereof may be varied within the 4scope of the following claim.

I claim: u

A safety switch for use in association with a system of elevator doors and the like comprising a sealed casing, a pair of spaced contacts supported within said casing, an actuator to com-I j' plete a circuit through said contacts,` an electrl-i cally conductive actuator guide member securedto said casing and having an elongated bore ex-V tending into said casing to direct the actuator into position between the contacts, said actuator having an insulating portion normally in contact with said guide member and an electrically conductive tip to cooperate with said contacts, saidguide.,`

element and said contacts being connected through a source of electrical energy, said circuit beingarranged so lthat when completed through the guide member a flow of current may; take place through at least one of said contacts, means electrically connected with the guide to render the circuit permanently inoperative when the circuit is completed through the guide, said actuator being moved by the elevator door or the like to render a circuit through the contacts operative when the door or the like is closed and to render said circuit through the contacts inoperative when the door or the like is open, and said guidemember circuit normally being maintained open by reason of its contact with the insulated por tion of the actuator but the guidemember circuit iunctloning to render the entire circuit permanently inoperative when a substitute electrically conductive actuator is substituted for the actuator that cooperates with the door or the like whereby the circuit through the guide member is completed.

FELICE PETRULLO.

REFERENCES CITED AThe followingl references are or record in the le of this patent:

' UNITED STATES PATENTS Great Britain Nov. 15, l1937 

